1. Field of the Invention
This patent application concerns a system for automatically detecting the position of items loaded on a conveyor belt and the conveyor belt for actuating the process.
2. Description of the Related Art
It is common knowledge that particularly practical conveyor belts today exist on the market provided with an overhead belt with windows in which the items to convey or sort are hooked, supported and conducted in a bearing structure consisting of metal pipes.
These plants have an electronic control unit which identifies both the items as they are loaded and each hooking window along the conveyor belts; by combining these two sets of data, said systems can constantly identify which particular item occupies a specific window of the conveyor belt.
This data is in fact essential to the systems for the successive automatic and accurate unloading of a particular item from the relevant conveyor belts, according to the orders received.
It should be noted however that in these conventional systems the identification and loading phase of the items into each specific window on the conveyor belt is particularly complicated.
The operator must in fact firstly identify the item to load by means of an optical sensing device which reads the bar code allocated to the item and then transmit a request to the system to load the item; on the basis of this request, the system stops with an empty window in front of a loading station, into which the operator hooks the item.
As mentioned above, the system associates the code of a particular item to the specific window into which the item is loaded; in particular, this is possible in that the electronic control unit in the system detects, as from a reference window on the belt identified conventionally with the number of zero, the progressive number of each window transiting at the loading station.
It follows that these systems, in terms of the principle adopted of associating a specific item to a specific window, are characterised in that the same identify the window to which a particular item is to be hooked even before the item itself has been loaded.
The consequence of this principle is that the operator is forced to load each item into that window as determined in advance by the system's control unit; the fact that the window stops at the loading station allows the operator to check the window selected by the control unit for a particular item.
From a practical point of view, the operator generally identifies the loading window by means of a display that indicates the number of the pre-selected window (if all the windows of the belt are numbered) or, alternatively, the pre-selected window is stopped in front of a reference index.
The intermittent feed of the conveyor belt, which is necessary to load the items as required, is in fact the major inconvenient of existing systems and substantially limits the operating speed.
Moreover, this inconvenient is particularly penalising in the case of those systems with several loading stations manned by the different operators; in this case the stops of the conveyor belt are extremely frequent in that each loading operator can autonomously stop the belt.